Search Results - EGA European Genome-Phenome Archive

HIV-phyloTSI: Subtype-independent estimation of time since HIV-1 infection for cross-sectional measures of population incidence using deep sequence data

Estimating the time since HIV infection (TSI) at population level is essential for tracking changes in the global HIV epidemic. Most methods for determining TSI give a binary classification of infections as recent or non-recent within a window of several months, and cannot assess the cumulative impact of an intervention. We developed a Random Forest Regression model, HIV-phyloTSI, which combines measures of within-host diversity and divergence to generate continuous TSI estimates directly from viral deep-sequencing data, with no need for additional variables. HIV-phyloTSI provides a continuous measure of TSI up to 9 years, with a mean absolute error of less than 12 months overall and less than 5 months for infections with a TSI of up to a year. It performs equally well for all major HIV subtypes based on data from African and European cohorts. We demonstrate how HIV-phyloTSI can be used for incidence estimates on a population level.

Study EGAS50000000895

Targeted sequencing (paired) of HR genes in primary and metastatic patient-derived xenografts (PDXs) of colorectal cancer (CRC)

Chemotherapy is the standard-of-care treatment for metastatic colorectal cancer (mCRC) and benefits some patients, but what distinguishes responders from non-responders is unclear. In this study, we leveraged a comprehensive collection of 69 molecularly annotated patient-derived xenografts to uncover functional predictors of response to 5-FU and irinotecan combination therapy (FOLFIRI) in mCRC. Genetic analyses revealed that treatment sensitivity was marked by genomic scars indicative of BRCAness, suggesting homologous recombination (HR) deficiency as a key determinant. Accordingly, we surveyed a manually curated panel of 44 genes with a documented role in HR for the potential presence of pathogenic mutations. We did not observe a specific enrichment of HR gene mutations based on response to FOLFIRI. This result, combined with the absence of widespread biallelic inactivation of the analyzed genes and the predominance of mutations categorized as variants of unknown significance, suggests that FOLFIRI sensitivity is not primarily governed by underlying mutations in HR genes responsible for mitigating the genotoxic effects of this therapeutic regimen.

Study EGAS50000000075

Shallow Whole Genome Sequencing of Patient Derived Xenografts

Chemotherapy is the standard-of-care treatment for metastatic colorectal cancer (mCRC) and benefits some patients, but what distinguishes responders from non-responders is unclear. In this study, we leveraged a comprehensive collection of 27 molecularly annotated patient-derived xenografts to uncover functional predictors of response to 5-FU and irinotecan combination therapy (FOLFIRI) in mCRC. Genetic analyses revealed that treatment sensitivity was marked by genomic scars indicative of BRCAness, suggesting homologous recombination (HR) deficiency as a key determinant. Accordingly, we surveyed a manually curated panel of 44 genes with a documented role in HR for the potential presence of pathogenic mutations. We did not observe a specific enrichment of HR gene mutations based on response to FOLFIRI. This result, combined with the absence of widespread biallelic inactivation of the analyzed genes and the predominance of mutations categorized as variants of unknown significance, suggests that FOLFIRI sensitivity is not primarily governed by underlying mutations in HR genes responsible for mitigating the genotoxic effects of this therapeutic regimen.

Study EGAS50000000191

Hyperdiploidy impairs fetal hematopoietic progenitor cell fitness and differentiation enabling persistence of rare preleukemic aneuploid clones

Cells previously cryopreserved in FBS-10%DMSO were thawed and resuspended in 1mL of cold lysis buffer (10 mM Tris-HCl pH 7.4, 154 mM NaCl, 0.2% BSA, 0.1% NP-40, 1 mM CaCl₂, 0.5 mM MgCl₂ in ultra-pure water) to lyse the cell membrane and release intact nuclei. The nuclei were stained with propidium iodide (10 µg/mL) and Hoechst 33258 (10µg/mL) to facilitate sorting based on cell cycle state and viability. Single nuclei from 48 cells per sample were isolated into 96-well plates containing 5µL of freeze buffer (1X PBS, 7.5% DMSO, and 40% ProFreeze freezing medium (Lonza)) using a MoFlo Astrios cell sorter (Beckman Coulter) at the Flow Cytometry Unit of the University Medical Center Groningen (UMCG), Netherlands. The plates were centrifuged at 500 g and stored at -80°C until library preparation. Single-nuclei libraries were prepared using a Bravo Automated Liquid Handling Platform (Agilent Technologies). Nuclei were lysed, and DNA was labelled with unique 10 bp dual barcodes and amplified as previously described. Sequencing was performed on an Illumina NextSeq 2000 platform with 77bp single end reads. The generated data were subsequently demultiplexed using sample-specific barcodes and converted to FASTQ files with bcl2fastq. Sequencing reads were aligned to the GRCh38/hg38 human reference genome using Bowtie2 (v2.2.4), and duplicate reads were marked with BamUtil (v1.0.3). Single-cell karyotypes were determined by performing copy number analysis using AneuFinder (v4.3.3) (https://github.com/ataudt/aneufinder). The analysis included GC-content correction and blacklisting of artifact regions identified from euploid controls. Copy number calling was conducted with the dnacopy and edivisive algorithms, employing a bin size of 1 Mb and a step size of 500 Kb. Libraries with an average of fewer than 10 reads per chromosome copy per bin or less than 95% concordance between the two algorithms were excluded from analysis. Whole-chromosome aneuploidies were identified when over 95% of bins exhibited deviation from the disomic state. Aneuploidy scores were calculated as weighted averages of absolute copy number deviations from the euploid state.

Dataset EGAD50000002314

RTEL1 mutation as a modifier of Dyskeratosis Congenita in a family with a Telomerase RNA (hTR) template mutation and variant telomeric repeats

Vertebrate telomeres, the sequences protecting the end of linear chromosomes, are composed of conserved hexameric GGTTAG repeats. Here we present a C50>A telomerase RNA template mutation that results in the incorporation of the variant telomeric repeat GTTTAG in a family with dyskeratosis congenita primarily presenting as idiopathic pulmonary fibrosis. The mutant telomerase is characterized by decreased processivity in direct telomerase activity assays and in vivo based on data from Illumina next-generation whole genome sequencing and Oxford Nanopore Technologies long-read telomere sequencing. The latter provided positional mutant repeat information that revealed the inheritance and maintenance of proximal mutant repeats in individuals who did not inherit the template mutation. Additionally, we describe an RTEL1 nonsense mutation that is associated with very short telomeres in progeny harboring wild-type telomerase and inherited mutant telomeric repeats in the absence of overt clinical phenotypes. In contrast, co-inheritance of the RTEL1 nonsense and TERC r.C50>A mutations coincided with severe early-onset DC phenotypes in two individuals.

Study EGAS50000001644

Spatial predictors of response to immunotherapy in microsatellite stable metastatic colorectal cancer

Microsatellite stable (MSS) colorectal cancers (CRC) are largely unresponsive to immune checkpoint inhibition (ICI), prompting investigation into strategies to enhance sensitivity. The MAYA trial, which utilized temozolomide (TMZ) in MGMT-silenced MSS mCRC, hypothesized that TMZ-induced hypermutation could sensitize tumors to ICI. This phase II trial met its primary endpoint, demonstrating durable clinical responses with TMZ combined with ipilimumab and nivolumab. To elucidate factors influencing response heterogeneity, we conducted multi-omic spatial profiling of samples from patients who participated in the MAYA trial, including baseline and on-treatment tissue and blood specimens. While increased neoantigen load following TMZ exposure did not consistently predict for deep responses, spatial profiling revealed key determinants. Lymphocyte proportions, particularly CD8+KI67+ cells, within stromal and tumor compartments, along with macrophage composition (CD68+CD163+ cells) at the tumor-stromal interface, were predictive of response. Treatment pressures dynamically altered the tumor microenvironment composition and activated peripheral immune cells. This study is the first to identify spatial predictors of response to this promising novel treatment approach for MSS CRC.

Study EGAS50000001567

Fragmentomics Uncover Non-Mutational HRD Features

Homologous recombination deficiency (HRD) is a key biomarker in prostate cancer (PCa), predicting response to PARP inhibitors and platinum-based therapies. However, current diagnostics often rely solely on BRCA1/2 mutations or genomic scars, missing cases driven by other mechanisms. Tissue-based testing is further limited by tumor heterogeneity and biopsy challenges in metastatic bone disease. Here, we applied a comprehensive multimodal approach to assess HRD in 106 advanced PCa patients using circulating tumor DNA (ctDNA). This included targeted sequencing of homologous recombination repair (HRR) genes, low-pass WGS for genomic instability (sHRD), WES for mutational signatures, and cfDNA fragmentomics and chromatin accessibility profiling. BRCA2 was the most frequently altered gene, often co-occurring with PTEN loss. High sHRD scores correlated with BRCA2/RB1 loss, somatic copy number alterations, and poor survival. HRD tumors showed enrichment of SBS3/ID6 signatures, altered fragment lengths, and reduced accessibility at zinc finger transcription factor sites. These results support ctDNA-based multimodal profiling as a non-invasive strategy for HRD detection and stratification.

Study EGAS00001008190

Host factors dictate gut microbiome alterations in chronic kidney disease more strongly than to kidney function

Despite recent progress, microbial markers in Chronic Kidney Disease (CKD) remain inconclusive. We combined quantitative faecal metagenomics (N=130 CKD cohort) and cross-study biomarker comparisons (Ntotal=4420) to study microbiome associations with glomerular filtration rate (eGFR; kidney function) and 4-year CKD progression. Transit time (TT) and medications primarily explained microbiome variation, trumping eGFR-related effects. Metagenome analysis showed increased p-cresol and indole synthesis potential and decreased plant-to-animal CAZyme ratios with lower eGFR, coupled to a Bact1 to Rum enterotype shift, suggesting saccharolytic-to-proteolytic microbiome transitions linked to dietary guidelines and slowed-down TT. Peritoneal dialysis patients showed increased (dysbiotic) Bact2 prevalence and linked intestinal inflammation. Only Escherichia coli, an unnamed Alistipes species and Bifidobacterium adolescentis were confounder-independent markers for eGFR, but these nor previous markers convincingly replicated across 11 studies. No predictors for CKD progression were found. Together, poor evidence for microbiome biomarkers but substantial eGFR-independent effects were found, suggesting potential for nutritional and TT interventions in CKD.

Study EGAS50000000646

Distinct genomic profiles and clinical outcomes in constitutional mismatch repair deficiency-associated high-grade gliomas: insights into mutational signatures and clonal evolution

Constitutional mismatch repair deficiency (CMMRD) is a rare cancer-predisposition syndrome, yet the mutational processes and clonal evolution of CMMRD-associated high-grade gliomas (HGGs) remain incompletely understood. In this study, mutational signatures and tumor evolution were analyzed in 25 CMMRD-associated HGGs. Germline biallelic mutations were most frequently identified in MSH6 (56.0%), followed by PMS2 (36.0%) and MLH1 (8.0%). Affected patients showed very early disease onset (mean 5.8 years) and poor clinical outcomes, with a mean progression-free survival of 16 months. Distinct genomic and clinical differences were observed between MSH6- and PMS2-associated tumors. MSH6-deficient HGGs were enriched for SBS6, whereas PMS2-deficient tumors showed predominance of SBS21, and these mutational signatures were correlated with prognosis. Clonal evolution analyses revealed early involvement of POLE/POLD1 mutations and persistence of the founding clone at recurrence. Overall, the study highlights the importance of mutational signatures and clonal evolution in shaping tumor behavior and clinical outcomes in CMMRD-associated HGGs.

Study EGAS50000001506

TGF-β signaling mediates microglial resilience to spatiotemporally restricted myelin degeneration

Microglia survey and regulate central nervous system myelination during embryonic development and adult homeostasis. However, whether microglia-myelin interactions are spatiotemporally regulated remains unexplored. By examining spinal cord white matter tracts, we found that myelin degeneration was particularly prominent in the dorsal column (DC) during normal aging. This was accompanied by molecular and functional changes in DC microglia as well as an upregulation of TGF-β signaling. Disrupting TGF-β signaling in microglia led to unchecked microglial responses and myelin loss in the DC, accompanied by neurological deficits exacerbated with aging. snRNA-seq revealed the emergence of a TGF-β signaling-sensitive microglial subset and a disease-associated oligodendrocyte subset, both spatially restricted to the DC. We further discovered that microglia rely on a TGFβ autocrine mechanism to prevent damage of myelin in the DC. These findings demonstrate that TGF-β signaling is indispensable for maintaining microglial resilience to myelin degeneration in the DC during the aging process. This highlights a previously unresolved checkpoint mechanism of TGF-β signaling with regional specificity and spatially restricted microglia-oligodendrocyte interactions.

Study EGAS50000001413

Djerroudi et al., E-cadherin inactivation shapes tumor microenvironment specificities in invasive lobular carcinoma

Invasive lobular breast carcinoma (ILC) shows specific stromal features, T lymphocyte infiltration (TIL) being associated with poor prognosis. Here, we reveal the involved mechanism by performing single cell RNA sequencing, combined immunohistochemistry, deconvolution of bulk RNA sequencing from large retrospective ILC series, and functional assays using primary cells. We show that ILC accumulate FAP+ inflammatory cancer-associated fibroblasts (iCAF) through a previously undescribed mechanism mediated by E-cadherin/CDH1 on CAF plasticity. Indeed, CDH1 inactivation in ILC cancer cells prevents differentiation of iCAF into myofibroblastic CAF (myCAF), leading to iCAF accumulation. In turn, iCAF increase TIL infiltration and shape their spatial organization in ILC. Subsequently, CDH1-inactivated ILC cancer cells promote immune escape by lack of retention and activation of ITGAE-expressing resident memory CD8+ T lymphocytes (TRM). Hence, our study uncovers reciprocal interactions between CDH1-inactivated cancer cells, iCAF and CD8+ TRM, revealing why and how TILs have a poor prognosis in ILC patients, a mechanism extrapolated to other CDH1-mutated cancer types.

Study EGAS50000000761

Inferring tumor genomes from peripheral blood i.e. CTCs and plasma-DNA using deep sequencing and targeted enrichment

In this study we tested whether complex tumor genomes can be inferred from the peripheral blood (plasma DNA /CTCs) of 32 patients with stage IV colorectal carcinoma (CRC). To establish the percentage of mutated plasma DNA fragments we used 8 patient samples with different plasma DNA size distributions and KRAS mutations in their corresponding primary tumors and employed ultra-deep pyrosequencing with 3 different sequencing reaction sizes (i.e., 119 bp, 168 bp, and 323 bp). Furthermore, we used massive parallel sequencing of a panel of 68 CRC-associated genes to establish the mutation spectrum of cancer driver genes in the primary tumors, metastases, and CTCs of two colorectal cancer patients. To investigate, whether mutations found in only one CTC (“private CTC mutations”) are true mutations occurring with allele frequencies below the resolution limits of current detection methods, or whether they are amplification or sequencing artifacts, we performed ultra-deep sequencing of the primary tumors, metastases, plasma DNAs and normal tissues.

Study EGAS00001000337

Passive and active DNA methylation and the interplay with genetic variation in gene regulation

DNA methylation is an essential1 epigenetic mark whose role in gene regulation and its dependency on genomic sequence and environment are not yet fully understood2,3. In this study we provide novel insights into the mechanistic relationships between genetic variation, DNA methylation and transcriptome sequencing data in three different cell-types of the GenCord human population cohort4. We find that the association between DNA methylation and gene expression variation among individuals are likely due to different mechanisms from those establishing methylation-expression patterns during differentiation. Furthermore, cell-type differential DNA methylation may delineate a platform in which more local inter-individual changes may respond to or act in gene regulation. We show that unlike genetic regulatory variation, DNA methylation alone does not significantly drive allele specific expression.. Finally, inferred mechanistic relationships using genetic variation as well as correlations with TF abundance reveal both a passive and active role of DNA methylation to regulatory interactions influencing gene expression.

Study EGAS00001000446

ABO: a 3D stroma-supported culture platform enabling full human B lymphopoiesis for disease modeling and gene therapy development

Defective B-cell development underlies a large proportion of inborn errors of immunity, but progress in understanding disease mechanisms and of developing therapies has been limited by inadequate human in vitro models. Here, we establish a 3D aggregate culture platform composed of hematopoietic stem and progenitor cells (HSPCs) and mouse bone marrow stromal cells as an assay for efficient B-cell output (the ABO platform). ABOs supported progression through pro-B, pre-B, immature, and transitional B-cell stages, with a transcriptional profile and B-cell receptor (BCR) repertoire diversity closely resembling human bone marrow B-cell ontogeny. ABO-derived B cells exhibited functional signaling and differentiated into class-switched memory and antibody-secreting B cells following CD40-mediated stimulation. The ABO platform reproduced the arrest in B-cell development observed in RAG1-SCID patient–derived HSPCs, which was corrected by lentiviral RAG1 gene therapy. Thus, ABOs provide a clinically relevant platform for modeling B-cell immunodeficiencies and evaluating therapeutic strategies.

Study EGAS50000001693

Mutant KIT as imatinib-sensitive target in metastatic sinonasal carcinoma (H021)

Sinonasal carcinomas (SNCs) comprise various rare tumor types that are characterized by marked histologic diversity and largely unknown molecular profiles, yet share an overall poor prognosis owing to an aggressive clinical course and frequent late-stage diagnosis. The lack of effective systemic therapies for locally advanced or metastatic SNC poses a major challenge to therapeutic decision making for individual patients. Here, we used whole-exome and transcriptome sequencing to identify a KIT exon 11 mutation (c.1733_1735del, p.578_579del) as actionable target in a patient with metastatic SNC whose tumor, despite all diagnostic efforts, could not be assigned to any known SNC category and was refractory to multimodal therapy. Molecularly guided treatment with imatinib resulted in a dramatic and durable response with remission of nearly all tumor manifestations, indicating a dominant driver function of mutant KIT in this tumor. This observation highlights the potential of unbiased genomic profiling for uncovering the vulnerabilities of individual malignancies, particularly in rare and unclassifiable tumors, and underscores that KIT exon 11 mutations represent tractable therapeutic targets across different histologies.H021

Study EGAS00001001845

Mutational signature in colorectal cancer induced by genotoxic pks+ E. coli

Various species of the intestinal microbiota have been associated with the development of colorectal cancer (CRC), yet a direct role of bacteria in the occurrence of oncogenic mutations has not been established. Escherichia coli can carry the pathogenicity island pks, which encodes a set of enzymes that synthesize colibactin. This compound alkylates DNA on adenine residues and induces double strand breaks in cultured cells. Here, we exposed human intestinal organoids to genotoxic pks+ Escherichia coli by repeated luminal injection over a period of 5 months. Whole genome sequencing (WGS) of clonal organoids before and after this exposure reveals a distinct mutational signature, absent from organoids injected with isogenic pks-mutant bacteria. The same mutational signature is detected in a subset of 3668 human metastatic cancer genomes, predominantly in a subset of CRC cases. Our study describes a distinct mutational signature in CRC and implies that the underlying mutational process directly results from past exposure to bacteria carrying the colibactin-producing pks pathogenicity island.

Study EGAS00001003934

Whole Genome Sequencing of Gingivo-buccal Cancer: ICGC-India Project_YR03

As a part of the ICGC, India has undertaken genomic studies on gingivobuccal cancer of the oral cavity, which is the most prevalent form of cancer among men in India. There are various known environmental (life-style) correlates of this cancer, the most important of which are tobacco chewing and HPV infection. Whole genome sequencing of paired DNA samples – isolated from the tumor tissue and from the blood of twenty five patients – have been performed to catalog germline and somatic mutations. Association between each observed genomic alteration and exposure to environmental risk factors is being explored. Detailed clinical characterization of the patients, collection of data on demographic and environmental exposures, and isolation of DNA samples from blood and tumor tissues collected from each patient are being done at the Advanced Centre for Research, Treatment and Education on Cancer, Mumbai. Whole genome sequencing is being performed at the National Institute of Biomedical Genomics, Kalyani. We have completed whole genome sequencing of paired blood and tumor DNA samples using Illumina HiSeq-2000 and 2500.

Study EGAS00001001901

Genomic Analyses Identify Recurrent MEF2D Fusions in Acute Lymphoblastic Leukemia

Chromosomal rearrangements are initiating events in acute lymphoblastic leukemia (ALL). Here, using RNA-sequencing (RNAseq) of 560 ALL cases, we identify rearrangements between MEF2D (myocyte enhancer factor 2D) and five genes (BCL9, CSF1R, DAZAP1, HNRNPUL1 and SS18) in 22 B progenitor ALL (B-ALL) cases with a distinct gene expression profile, the most common of which is MEF2D-BCL9. Examination of an extended cohort of 1164 B-ALL cases identified 30 cases with MEF2D rearrangements which include an additional fusion partner, FOXJ2, thus MEF2D-rearranged cases comprise 5.3% of cases lacking recurring alterations. MEF2D-rearranged ALL is characterized by a distinct immunophenotype, DNA copy number alterations at the rearrangement sites, older diagnosis age, and poor outcome. The rearrangements result in enhanced MEF2D transcriptional activity, lymphoid transformation, activation of HDAC9 expression and sensitive to histone deacetylase inhibitors treatment. Thus, MEF2D-rearranged ALL represents a distinct form of high-risk leukemia, for which new therapeutic approaches should be considered.

Study EGAS00001001952

Somatic pathogenic variants in the normal mammary gland of sporadic breast cancer patients.

The mammary gland undergoes hormonally stimulated cycles of proliferation, lactation and involution. We hypothesized that these factors increase the mutational burden in glandular tissue and may explain high cancer incidence rate in the general population and recurrent disease. Hence, we investigated the DNA sequence variants in the normal mammary gland, tumor and peripheral blood from 52 reportedly sporadic breast cancer patients, including breast-conserving surgery cases. Targeted resequencing of 542 cancer associated genes revealed mosaic somatic pathogenic variants of: PIK3CA, TP53, AKT1, MAP3K1, CDH1, RB1, NCOR1, MED12, CBFB, TBX3 and TSHR in the normal mammary gland, at considerable allelic frequencies (9x10-2 to 5.2x10-1) indicating clonal expansion. Further evaluation of the frequently damaged PIK3CA and TP53 genes by ultra-sensitive duplex sequencing demonstrated a diversified picture of multiple low level-mosaic (in 10-2 to 10-4 alleles) hotspot pathogenic variants. Our results raise a question about the oncogenic potential in non-tumor mammary gland tissue of breast-conserving surgery patients.

Study EGAS00001005698

Population_dynamics_in_abnormal_haematopoiesis

Background: Our recent study has made direct insight into the clonal dynamics of blood cell production in an unperturbed setting in a human. Using whole genome sequencing to track acquired somatic mutations, we were able to construct a phylogenetic tree of different stem and progenitor cells and used this tree to determine the dynamics of mature blood cell production in longitudinal samples. These data set the baseline for understanding population dynamics in abnormal haematopoiesis, and how malignant clones outcompete their normal counterparts to drive haematological malignancies. Aim: This study will measure population dynamics in abnormal human haematopoiesis in patients with clonal blood stem cell disorders. Methods: From patient bone marrow or peripheral blood, we have isolated colonies grown from single blood stem cells/progenitors. Colony DNA will be analysed by whole-genome sequencing to build (or populate) a phylogenetic tree to determine clonal relationships and track stem cell contribution to mature blood cell production. These data will also reveal disease-associated genomic features (mutational burden and mutational signatures) in haematopoietic cells.

Study EGAS00001003181

Analysis of mechanisms of CD19- relapse following novel low affinity CD19 Chimeric Antigen Receptor (CAR) T-cells (CD19 CAR T-cells) in a Phase I clinical study in paediatric ALL: CARPALL

Phase I clinical study (CARPALL, NCT02443831) utilizing a novel low affinity CD19CAR CAR in patients age <25 with high risk CD19+ ALL. Seventeen patients were enrolled and 14 received an infusion of CAR T cells. Among those achieving complete remission, 6 subsequently relapsed, 5 with CD19- disease, 1 with CD19+ disease. Whole exome sequencing of bone marrow DNA from patients with CD19- relapse showed mutations in the CD19 gene predicted to result in loss of surface expression in 4/5 patients. These mutations were not detectable prior to CAR T cell therapy. With a median follow-up of 14 months, 5/14 patients (36%) are alive and disease-free. Overall survival was 84% at 6 months and 63% at 12 months and by the criteria used in the ELIANA study, event-free survival was 67% and 46%. Using more stringent criteria where an event is defined as molecular relapse, molecular EFS was 55% and 29 %. The median duration of remission in responding patients was 7.4 months.

Study EGAS00001003733

Sequencing of an organoid biobank for childhood kidney cancers that captures disease and tissue heterogeneity.

Kidney tumors are among the most common solid tumors in children, comprising several distinct subtypes differing in many aspects, including cell-of-origin, genetics, and pathology. Pre-clinical cell models capturing the disease heterogeneity are currently lacking. Here, we describe the first pediatric cancer organoid biobank. It contains tumor and matching normal organoids from over 50 children with different subtypes of kidney cancer, including Wilms tumors, malignant rhabdoid tumors, renal cell carcinomas, and congenital mesoblastic nephromas. The malignant rhabdoid tumor organoids represent the first organoid model for tumors of non-epithelial origin. The tumor organoids retain key properties of native tumors, useful for revealing patient specific drug vulnerabilities. We further demonstrate that organoid cultures derived from Wilms tumors consist of multiple different cell types, including epithelial, stromal and blastemal-like. Our organoid biobank captures the cellular heterogeneity of pediatric kidney tumors, providing a representative collection of well-characterized models for basic cancer research, drug-screening, and personalized medicine.

Study EGAS00001003853

CD8+ T-cell exhaustion induced by leukemic cells drives progression in Chronic Lymphocytic Leukemia

In order to shed light on mechanisms that lead to CLL progression, we investigated longitudinal changes in both the genetic and immunological landscapes. For that, we analyzed paired samples obtained from CLL patients at diagnosis and progression before front-line treatment or at diagnosis and long-term asymptomatic follow-up. By whole-exome sequencing (WES), we found that CLL cells displayed limited genetic evolution at progression. Conversely, T cells from progressing patients showed significant immunophenotypical and transcriptional changes over time not observed in patients that did not progress. Specifically, we found that CD8+ T cells at progression were characterized by an increasing terminally exhausted effector phenotype (T-betdim/- Eomeshi PD1hi) with high co-expression of inhibitory receptors (PD1, CD244 and CD160). This exhausted status in CD8+ T cells was induced by progressing leukemic cells mainly through a mechanism dependent on soluble factors, including IL-10. Thus, we demonstrate that immunological changes are of paramount importance for CLL clinical progression, thereby providing a rationale for the use of early immunotherapeutic intervention in this disease.

Study EGAS00001004116

SNP array files, IDAT files, from 34 members of a Family with a high prevalence of psychosis

We investigated the genetic causes of major mental disorders (MMDs) including schizophrenia, bipolar disorder I, major depressive disorder, and attention deficit hyperactive disorder, in a large family pedigree from Alpujarras, South of Spain, a region with a high prevalence of psychotic disorders. We applied a systematic genomic approach based on karyotyping (N=4), genotyping by genome-wide SNP array (N=33), whole-exome sequencing (N=4), and whole-genome sequencing (N=12). We performed genome-wide linkage analysis, family-based association analysis, and polygenic risk score estimates. Significant linkage was obtained at chromosome 9 (9q33.1-33.2, LOD score= 4.11), a suggestive region that contains five candidate genes ASTN2, BRINP1, C5, TLR4, and TRIM32, previously associated to MMDs. Comprehensive analysis associated the MMD phenotype with genes of the immune system with dual brain functions. Moreover, the psychotic phenotype was enriched for genes involved in synapsis. These results should be considered once studying the genetics of psychiatric disorders in other families, especially the ones from the same region, since founder effects may be related to the high prevalence.

Study EGAS00001004592

The genetic structure of Norway

The aim of the present study was to describe the genetic structure of the Norwegian population using genotypes from 6369 unrelated individuals with detailed information about places of residence. Using standard single marker- and haplotype-based approaches, we report evidence of two regions with distinctive patterns of genetic variation, one in the far northeast, and another in the south of Norway, as indicated by fixation indices, haplotype sharing, homozygosity and effective population size. We detect and quantify a component of Uralic Sami ancestry that is enriched in the North. On a finer scale, we find that rates of migration have been affected by topography like mountain ridges. In the broader Scandinavian context, we detect elevated relatedness between the mid- and northern border areas towards Sweden. The main finding of this study is that despite Norway’s long maritime history and as a former Danish territory, the region closest to mainland Europe in the south appears to have been the most isolated region in Norway, highlighting the open sea as a barrier to gene flow into Norway.

Study EGAS00001004826

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